Increasing the power density of power supplies has been a major concern in recent years. Such concern has led to advancements in high frequency capacitive and magnetic components which are small and efficient. Moreover, there have been significant developments in HVIC power supply technology. For example, an HVIC DC-to-DC conversion type power supply employing a half-bridge converter is described in Steigerwald et al. U.S. Pat. No. 4,694,384, issued Sept. 15, 1987 and assigned to the instant assignee. The HVIC power supply of the Steigerwald et al. patent, which is hereby incorporated by reference, has a two-chip architecture for primary side and secondary side control. The primary side control chip employs a digital data detector for communication with the secondary side control chip via a pulse transformer. Advantageously, the Steigerwald et al. power supply may be operated in either a pulse width modulated (PWM) mode or a resonant mode.
The small size and versatility of the hereinabove described Steigerwald et al. power supply make it attractive for many commercial half-bridge power supply applications. However, it is desirable to reduce power supply size even further, while increasing versatility to operate in additional control modes. Furthermore, it is desirable to provide an HVIC control chip having the capability of controlling either a full-bridge or a half-bridge power supply in multiple control modes, as desired.